To stably keep a heating level for an analyzed specimen fed into a specimen analyzer at a prescribed level, so as to eliminate dispersion in analytical results caused by a temperature difference among the analyzed specimens.

This specimen heater B for heating the analyzed specimen A fed into the specimen analyzer C is provided, as main features, with a specimen heating unit HU arranged in a route D for carrying the analyzed specimen A into the analyzer C and provided with a heating casing 10 having heating tunnels 11-15 capable of passing the analyzed specimen A, a heat energy supplying unit EU for circulating a heating medium to radiators 21-26 provided in a wall part of the heating tunnels 11-15 to heat insides of the heating tunnels 11-15 to the prescribed temperature, and air shutters 41, 42 and 51, 52 arranged respectively in inlets and outlets of the heating tunnels 11-15 of the heating easing 10.